The Conversation
Dr. Terry F. Davies: Thank you, Sam, for agreeing to talk. Let’s start with your background. I know you are originally from Ruse, Bulgaria, on the border with Romania—correct?
Dr. Samuel Refetoff: Yes. Ruse is on the Danube River which separates Romania from Bulgaria. The reason the city became quite prominent was because one could easily travel to Vienna and Budapest by boat. Bulgaria is quite large
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and still has a small population of about 7 million. It has little industry, so it is not polluted, and the streams are still full of fish and wildlife. However, it is quite poor, and farming remains an important part of life.
Dr. Davies:
How come your family were there?
Dr. Refetoff:
My great-grandfather came as a young man to Bulgaria from Bosnia. The archives of Ruse have letters from my grandfather and my great-grandfather. Their ancestors were tax collectors for the Ottoman Turks and so they retreated (see Ref. 9) since they were fearful of remaining in Bosnia having worked for the Turks. They moved eastward and settled in Bulgaria. My great-grandfather became a lawyer; my grandfather received a doctorate in law from the Free University of Brussels, while my father became a banker. Actually, my father was partly responsible for the establishment of the University of Ruse.
Dr. Davies: From which I note you have an honorary doctorate, and you are also an honorary member of the Bulgarian Endocrine Society. So, they like you!
Dr. Refetoff: Indeed.
Dr. Davies: Was your mother also from Ruse?
Dr. Refetoff: No. My mother was from Philippopolis, the city of Phillip, the father of Alexander the Great. It’s on the south side of the Balkan Mountains and now it’s called Plovdiv. It has a preserved Roman amphitheater and is a popular tourist site.
Dr. Davies: So, you grew up in Ruse and I assume you went to high school there.
Dr. Refetoff: I went to a French day school run by the Sisters of Notre Dame de Sion where we were obligated to speak French, which became my best language. We had to leave Bulgaria in 1949 when I was 12 and I then finished high school in Antwerp, Belgium also at a French-speaking school.
Dr. Davies: So, it must have been a big decision for your family to pack up and go to Belgium.
Dr. Refetoff: We left during communism as it became dangerous for my father to remain in Bulgaria. The Second World War ended in Bulgaria in September 1944 with the arrival of the Soviet army. During 1948–49, people with financial means, not necessarily very rich, were being interned in concentration camps accused of acquiring wealth by exploiting the proletariat. Their names appeared in newspapers and they shortly after disappeared.
Dr. Davies: So, your parents knew what was going on very quickly?
Dr. Refetoff: My father’s name did appear in the paper. Having worked for the Franco Belgian Bank, he thought that he would easily find work in Belgium as he also spoke French. Arriving in Belgium he presented himself to the bank with the necessary documents but was told that the bank had no job for him. With no future in Belgium, we emigrated to Canada.
Dr. Davies: So, you settled in Montreal, French-speaking Canada, and it was time for college?
Dr. Refetoff: Yes. I first started at the Université de Montréal. I didn’t speak any English at the time, but I studied biochemistry. I went on to a graduate program for a PhD at McGill University, working with Charles Philippe Leblond
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where my first contact with thyroid began via autoradiography.
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Leblond had a lab next to that of Hans Selye
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who worked on stress mechanisms.
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In fact, Leblond and Selye had a stressful relationship. It got to a point where a tape was placed in the middle of the hallway and required people working for the respective lab walk on their side of the tape! Selye had monkeys on primate chairs in the cold room to induce stress which Leblond, who shared the same cold room, couldn’t stand. It was not a pleasant environment.
Dr. Davies: So, you gave up biochemistry at that point?
Dr. Refetoff: Not exactly—I completed a Masters in histology and was admitted to medical school at McGill. I failed my first year Christmas exams since I was using French books because my English was still poor and then I couldn’t understand the exam questions. So, I was summoned by the Dean who told me, “Sam, you need to get yourself an English-speaking girlfriend.” I got the message, and I did.
Dr. Davies: And so, you qualified from McGill eventually?
Dr. Refetoff: Yes, and I was planning to go to the London School of Tropical Medicine and Hygiene. By that time, I had been in the Amazon for several months and had developed an interest in tropical medicine through my idol Dr. Albert Schweitzer.
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I received a scholarship from the Canadian government but a few months before leaving for London I was notified that my scholarship was withdrawn as there were no tropical diseases in Canada! Following an advertisement for a vacant residency in Los Angeles, I ended up at the Good Samaritan Hospital. While there I applied to continue my training in Boston at the Lahey Clinic.
Dr. Davies: So, when did a career in endocrinology first appear in your mind?
Dr. Refetoff: My work doing radioautography on the thyroid in Leblond’s lab drew my interest in a family in Los Angeles who were from Mexico with suspected thyroid problems. My Attending Physician at Good Samaritan, Dr. Loren DeWind
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, got me involved. Briefly, a nonverbal girl was hit by a truck and found to have a goiter. A brother, also deaf nonverbal, had a goiter suggesting familial congenital hypothyroidism. However, all turned out to have high protein-bound iodine (PBI) levels causing some confusion!
Dr. Davies: So now we are talking about the first family that eventually would be described as having resistance to thyroid hormone.
Dr. Refetoff: Correct.
Dr. Davies: You understood some thyroid physiology at that point?
Dr. Refetoff: Well, yes, I think because of this family, I started reading and thinking about the thyroid.
Dr. Davies: So, this family had a high PBI but appeared more hypothyroid than hyperthyroid. And this is when you started to think about a lack of sensitivity to thyroid hormone, right?
Dr. Refetoff: It took some time before resistance appeared on the radar. One possibility was that they made the dextro amino acid form of thyroxine (T4), with no biological activity so they were not hyperthyroid. But they were not grossly hypothyroid either, though delayed bone age and deafness suggested hypothyroidism.
Dr. Davies: So how long had the PBI been around at that time? I can remember using PBIs when I was an intern, but I don’t know when it first came into use.
Dr. Refetoff: Determination of the iodine content in serum was a method used for the identification and quantitation of thyroid hormone,
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but the measurement of PBI was the earliest method to be widely used in the mid-1950s. It measured the total quantity of iodine precipitable with serum proteins, 90% of which is T4. Butanol extractable iodine (BEI) came later
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being more accurate for measuring T4. And then came the competitive binding assay. That was pioneered by Beverley Murphy and CJ Pattee in 1963
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who were in Montreal. And then of course came the radioimmunoassays.
Dr. Davies: But at the hospital where you were the resident, it was routine to do a PBI on patients?
Dr. Refetoff: Yes, right.
Dr. Davies: So, you studied these children with high PBIs and there was a bit of “resistance” to your ideas at that point. Isn’t that right?
Dr. Refetoff: There was and I needed some help. Loren De Wind, who got me involved, was a practitioner, very respected as an endocrinologist, but without expertise in thyroid investigation so it was difficult for the two of us to publish. When I arrived in Boston, I talked with Elmer Bartels
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who was at the Lahey clinic. He was physician to John F. Kennedy as a matter of fact. And he said, “You have to go and see a guy called John Stanbury.
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”
Dr. Davies: So, at this point, you hadn’t published anything, right?
Dr. Refetoff: No. I had published a paper in Annals of Internal Medicine about iatrogenic hydrothorax.
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We used to introduce indwelling catheters through the jugular vein, and somebody punctured the superior vena cava and was administering the fluid inside the pleural space.
Dr. Davies: I see that it is number 1 of your 600 papers. Well, those things happened. So, you were in Boston when you worked up this family more thoroughly?
Dr. Refetoff: I moved to Boston in 1965. The paper was published I think in 1967.
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I went to see Stanbury and while waiting for him a fellow I knew from Leblond’s lab (Bernard Benard) materialized and said, “Sam, what are you doing here?” I said, “I’m waiting, to show something interesting to Dr. Stanbury.” He said, “Come and show it to my boss.” His boss was Leslie De Groot.
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So, I showed DeGroot my results. He said, “You need to do an iodine kinetic study.” He gave me some radioactive iodide! I called the Good Samaritan Hospital, they liked me there, and the head of the hospital organized for me to return and stay there to perform the studies. I boarded the plane with 131I in my pocket!
Dr. Davies: Oh, my goodness.
Dr. Refetoff: In a lead container, but…
Dr. Davies: In New York City at that time some doctors gave radioiodine to the patients themselves in their office.
Dr. Refetoff: We did that also at the Brigham. My boss, Herb Selenkow
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used to give radioactive iodine directly to patients.
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At a certain point his badge was burned but it turned out, he hung his coat next to where the radioactive iodine was stored.
Dr. Davies: Good story. So, Les DeGroot advised you and knew what you needed to do to get published?
Dr. Refetoff: Yes. I flew back to Los Angeles and completed the kinetic studies during the Watts riots.
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The family lived in the Watts area where I went to get blood samples and collect urine. The hospital arranged an escort. There I was walking with four jugs of urine and four National Guards escorting me!
Dr. Davies: It worked out well. And so, once you published that paper, presumably other people said “I’ve got patients who look just like that.”
Dr. Refetoff: Actually, I first made a presentation at the 1966 Endocrine Society meeting in Chicago.
Dr. Davies: Right and the paper was published in 1967.
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Dr. Refetoff: I was interviewed about my 1966 presentation, so it was not completely poo-pooed. But it would have been difficult to publish without Les DeGroot being the third author. The concept of target tissue resistance to thyroid hormone came from Les. He made me incubate the labeled serum proteins with cobra venom that degrades only L amino acids followed by chromatography on paper. It was mostly degraded and so proved that it was L amino acids and so the patients produced l-thyroxine. So, resistance was the most likely explanation. Later, we actually brought the family to Chicago after J. Stanbury had them at the Massachusetts Institute of Technology.
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Dr. Davies: Really interesting. So, the paper comes out, and then what happens next? You go on working on a lot of different things including thyroxine-binding globulin (TBG) deficiency with Selenkow
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but there must have been some response to this concept of resistance?
Dr. Refetoff: It had to wait for more cases. The next description of resistance was 6 years later from Lamberg in Finland
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and then from Bruce Weintraub while working at the Thyroid Unit at the Massachusetts General Hospital in Boston
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Actually, Bruce was a medical student when I was a fellow at the Brigham. He came to Herb Selenkow to do something interesting. Herb directed him to me and I showed him that we were working on an assay for T3 which we later published with Ken Sterling
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We separated the T4 from T3 on paper chromatography and then measured the T3. It was not a direct assay with an antibody to T3. Bruce didn’t want to work in Selenkow’s lab but he published a few years later on resistance to thyroid hormone.
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Dr. Davies: So, this set you on your career path?
Dr. Refetoff: That work got me deeper into endocrinology. After finishing my fellowship, I became an instructor at the Brigham. Les DeGroot by that time had moved to Chicago and he recruited me to Chicago where I have remained. For many years I had an interest in general endocrinology, working, for example, on Cushing’s syndrome
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and diurnal hormone rhythms.
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But thyroid continued to be my primary interest.
Dr. Davies: There was quite a gap before the thyroid hormone receptor story explained resistance?
Dr. Refetoff: Yes indeed. Ron Evans
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characterized the β receptor gene
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and then Bjorn Vennstrom
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described the α receptor gene.
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Dr. Davies: Simultaneously was it not?
Dr. Refetoff: Yes, published in the same 1986 issue of the Nature journal. We then did linkage analysis using restriction enzymes in the large families to determine if the β receptor haplotype segregated with the phenotype but found no segregation! A former intern at the University of Chicago, Steve Usala,
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had moved to NIH with Bruce Weintraub and was doing the same work. He called or wrote to inform me that he found linkage and wanted to publish it. I told him using the same methodology we found no linkage. But they did publish their results in 1988.
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We went back and found that the samples of the grandfather and grandmother were accidentally reversed. Although the grandmother had died, we had her fibroblasts, checked them, and that is what happened, and we could then confirm linkage implicating the thyroid hormone receptor β. In 1989, we then published the first receptor mutation with Leslie DeGroot.
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Dr. Davies: Now that was a mutation or a deletion? There are some families with deletions, are there not?
Dr. Refetoff: That was a missense mutation, but there are indeed deletions. More common are single nucleotide deletions causing a frame shift. There are some deletions of 10–20 base pairs, and an even larger complete deletion was found only in the original first family, the one from the Good Samaritan Hospital in Los Angeles. Heterozygous individuals were not affected as they had no mutant allele to produce a dominant negative effect and inheritance was recessive.
Dr. Davies: Understood. Now these children don’t respond to thyroid hormones in the sense of helping their development?
Dr. Refetoff: They have mutations that reduce the binding affinity of T3 for the receptor, but not always to zero. In some it is mild, let’s say 80% of the normal affinity. Those people have mild elevation of thyroid hormones. They can be missed and symptomatically they may be completely normal.
Dr. Davies: But those that are affected are they improved by giving them thyroid hormone?
Dr. Refetoff: Yes and no. Most compensate very nicely by increasing their thyrotropin (TSH) and thyroid hormone levels. It’s what we used to call “generalized resistance.” It is shared by the brain, hypothalamus, pituitary, and it’s the β receptor that controls the response. If the receptor is not absent, then they can do well. They can also tolerate a higher level of thyroid hormone acting at their α receptor but tissues expressing mainly α, those tissues then are hyperthyroid. This is why some of the patients present with tachycardia because α is expressed in the heart and they have high thyroid hormone levels.
Dr. Davies: So, it can still be a clinical issue even now?
Dr. Refetoff: Yes, even now. The differential diagnosis is FDH—familial dysalbuminemic hyperthyroxinemia.
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Mutant albumins with high affinity for T4 may have falsely elevated T4 with a normal TSH. The other condition in the differential diagnosis is TSH-producing adenoma with TSH present in the presence of high thyroid hormone levels.
Dr. Davies: But there are still patients where, as I understand it, there are no mutations or deletions in the thyroid hormone receptors and are still thought to have resistance?
Dr. Refetoff: Yes, there are, but the majority are somatic mosaics, which may be hard to demonstrate because mosaicism is isolated to certain tissues. You might not find the mutation in a blood sample and of course you can’t take out a piece of pituitary!
Dr. Davies: Interesting. And of course, your research spans many other areas, not just what we’ve been concentrating on. How would you define the different phases of your career, obviously starting with resistance, then moving to the thyroxine-binding proteins (TBG)?
Dr. Refetoff: The TBG work I did early on as a fellow with Herb Selenkow. We published a girl with Turner’s syndrome and who was completely TBG deficient because her single X chromosome behaved as dominant.
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Much later we published the first mutation in the albumin gene producing FDH.
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But this was suspected from biochemical studies showing excess T4 precipitating with albumin. So, there was an earlier clue that albumin was at fault. So, I became interested in abnormal thyroid tests, especially related to congenital thyroid diseases and in that way, we became involved in other genetic defects affecting the thyroid.
Dr. Davies: Including the selenocysteine proteins
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and an area that I have been interested in is TSH resistance
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which you also pioneered.
Dr. Refetoff: Yes, but that was only after Gilbert Vassart
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demonstrated a gain in function mutation in the TSH receptor in 1993.
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I did not think about that receptor before their report. But later, in 1998, while in Belgium on sabbatical leave, we also identified a phenotype of high TSH and normal thyroid hormone levels without a TSH receptor gene mutation, dominantly inherited in a large family. I went to Israel to draw their blood and also to California where some lived. We ended with more than 80 family members. Now, 25 years later, we found a mutation in a primate-specific noncoding DNA region on chromosome 15q acting as an enhancer causing mild TSH resistance.
Dr. Davies: And that is your latest paper?
Dr. Refetoff: It will appear in Nature Genetics in May 2024.
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Interestingly, Sandra McLachlan
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and Basil Rapoport
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published thyroid function tests in primates
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and I noted that the gorillas had higher TSH without a decrease in free T4. We found they have mutations in the same DNA region. Somehow primates acquired it.
Dr. Davies: Fascinating. So, it’s not really a disease.
Dr. Refetoff: No, they have only a high TSH. Japanese workers also found some individuals with the same defect, and we decided to publish our data simultaneously. Their story is a little bit different because they screened all neonates with a high TSH.
Dr. Davies: So, during your career journey, I wrote down some of the many well-known people that you trained and forgive me if I miss important people out. I recognized Terry Smith, David Sarne, Ken Ain, Roy Weiss, Yoshitaka Hayashi, and Theodora Pappa just as a sampling as I skimmed through your very large CV.
Dr. Refetoff: There are many others. For example, Enio Martino known for amiodarone-induced hyper- and hypothyroidism
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and Joachim Pohlenz now chair of Pediatrics, in Mainz, Germany, who has identified mutations in the iodide symporter,
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TTF1,
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DUOX,
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and others.
Dr. Davies: Well, I do think our conversation has been fascinating and quite comprehensive and I thank you for being so open about your career. Before we finish, I do want to ask you about the American Thyroid Association (ATA). You’ve been a member for 50+ years and I’m sure you have some opinion about it. What can I draw out from you as positives and negatives?
Dr. Refetoff: The negatives are minor and, if there were many, I wouldn’t have remained as a member. Although I’ve been active in the ATA I have refused to run as president since I am not very good in politics. My concern, however, has always been the poor support for young people, the registration fees and the costs of attending the annual meeting. I have been vocal in that regard and I am pleased at the improvement but there are still a lot people interested in the thyroid with mentors who have no means to support them going to the meeting. The reason for less science at the ATA these days is I think financial. If you send a grant to NIH and your grant is on thyroid cancer, you have much more chance to be funded than if your grant is to study congenital thyroid diseases.
Dr. Davies: Yes indeed.
Dr. Refetoff: The study sections do not have thyroidologists—or at most one only.
Dr. Davies: Well, despite this, you have done very well over 50 years with the same NIH Grant so that is something to be very proud of, right?
Dr. Refetoff: Yes. It’s the same grant I have had. I am in my 50th year.
Dr. Davies: And now there is the Refetoff Fund at the ATA!
Dr. Refetoff: The Fund was not established by me but by former fellows and colleagues under the guidance of David Sarne who invites contributions (via the ATA website). I donate to the other funds at the ATA (such as the Galton and Ridgway Funds) and not the fund carrying my name!
Dr. Davies: We didn’t make time to mention your family which I would very much like to include as we end.
Dr. Refetoff: Of course. My first wife (Gunvor Thomsen) was Danish and from the countryside of Jutland. She died in 1978, when she was only 42 years old. So, it wasn’t easy to work with three young children. I eventually remarried. My current wife, Heather, née Bendall, is English from Hampshire, England. Her only children are mine but that has worked out very well for us. We have a son, Osceola, an art photographer in Los Angeles. Our first daughter, Solveig, studied philosophy and lives in Seattle. Her husband is employed by Microsoft. Our youngest daughter, Sofia, a PhD in zoology, lost her husband to pancreatic cancer. Her eldest daughter, just turned 22, graduated from Tulane and is going to medical school. All together I have five grandchildren to enjoy, one boy and four girls!
Dr. Davies: Wonderful! Thank you for sharing this with us and I want to thank you Sam for your time today. I know you are still very busy, and you still work every day. Have a good night.
Dr. Refetoff: Bye. Thank you. See you soon.
